Daffy's red swim cap (which he so carefully adjusts before going head-down) is missing when he confronts Porky.
When Daffy says "Wait", the words do not match with his mouth.
When Porky jumps out of the tree, he fires his double barrel shotgun 5 times. But double barrel can only fire twice and then has to be reloaded. Further, Porky then pumps the shotgun to load another round, but the shotgun just clicks. A double barrel shotgun is not a pump shotgun. And a pump shotgun has only one barrel, never two barrels. In short, a double barrel pump shotgun has never existed.